Why are there trade limitations?

Personally I like the two, though mainly for selfish ease of layout purposes ^^.  Like Chels said, I avoid hover whenever physically possible because I am a mainly mobile user and I know others are too! And hover is unreadable on most touch screens.  Laying out the trade/specialty combos is a huge challenge and what we have currently is workable, but it was challenging even with two lol!

That being said, I'm not completely against it and wouldn't shoot it down entirely for that reason haha! :). Trades are supposed to be super specialized skills however.  Every wolf can hunt, and every wolf can fight, so it's a skill level above to hold the mercenary or hunter trade.  They are the best of the best and practice often.  It isn't just something you achieve and bam, done.  

So realistically I see two being a good number.  That's just opinion! And if people disagree I don't mind looking at changing it :)